Inheritance

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Question 13

In mammals, females have two similar sex chromosomes ( $X$ and $X$ ) and males have two different sex chromosomes ( $X$ and $Y$ ).

However, in many insects (such as grasshoppers), females have two similar sex chromosomes ( $X$ and $X$ ), while males have only one sex chromosome ( $X$ ) and no corresponding second sex chromosome (denoted as $O$ ). This is known as the $X X / X 0$ sex-determination system.

Complete the genetic diagram to show how sex is inherited in these insects.

Genotype of male parent: $‾\underline{\qquad\qquad}$
Genotype of female parent: $‾\underline{\qquad\qquad}$
Gametes from male parent: $‾\underline{\qquad\qquad}$
Gametes from female parent: $‾\underline{\qquad\qquad}$
Genotypes of offspring: $‾\underline{\qquad\qquad}$
Sex of offspring: $‾\underline{\qquad\qquad}$

[4]

Grasshopper eggs contain nutrients that the growing embryo needs to develop outside the mother's body.

Suggest one food molecule (major nutrient) present in the yolk of a grasshopper egg and describe the role of this molecule in the growth and development of the embryo.

[2]

Suggest one advantage of the egg being enclosed in a water-resistant outer chorion (shell).

[1]

Grasshoppers are a rich source of calcium, but humans also require Vitamin D to utilize it. Give another source of Vitamin D in the human diet (or lifestyle) and describe the function of Vitamin D in humans.

[2]

The number of chromosomes in the gametes (sperm and egg) of grasshoppers is less than the number of chromosomes in their body cells. Explain how the correct number of chromosomes is maintained in the offspring across generations.

[3]

Inheritance

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Question 13

In mammals, females have two similar sex chromosomes ( $X$ and $X$ ) and males have two different sex chromosomes ( $X$ and $Y$ ).

Complete the genetic diagram to show how sex is inherited in these insects.

Genotype of male parent: $‾\underline{\qquad\qquad}$
Genotype of female parent: $‾\underline{\qquad\qquad}$
Gametes from male parent: $‾\underline{\qquad\qquad}$
Gametes from female parent: $‾\underline{\qquad\qquad}$
Genotypes of offspring: $‾\underline{\qquad\qquad}$
Sex of offspring: $‾\underline{\qquad\qquad}$

[4]

Grasshopper eggs contain nutrients that the growing embryo needs to develop outside the mother's body.

Suggest one food molecule (major nutrient) present in the yolk of a grasshopper egg and describe the role of this molecule in the growth and development of the embryo.

[2]

Suggest one advantage of the egg being enclosed in a water-resistant outer chorion (shell).

[1]

[2]

[3]

Inheritance

Question 13

Inheritance Questions

Inheritance

Question 13

Inheritance Questions